The present invention relates generally to packaging machines and, more particularly, to a system and method for visually inspecting cigarette packages during the fabrication process.
In cigarette manufacturing, quality control has become a matter of increasing attention. Poor packaging (i.e., packaging which does not conform with predetermined quality requirements) detracts from consumer perceptions of the quality of the packaged goods. Perfectly good items are routinely returned for refund and disposal if they are poorly packaged. On-line inspection during manufacture is one way of controlling packaging non-conformities. In an effort to enhance the on-line quality control capabilities of their production machines, many companies have turned to machine vision techniques wherein cameras are used to allow for inspection of the production process.
U.S. Pat. No. 5,101,609, issued to Cook, discloses a vision inspection system in which a cigarette packaging machine is modified to include an inspection indexing wheel. The inspection indexing wheel is positioned at a post-construction location along the manufacturing process at which the cigarette packages have already been fully constructed.
There exists a need for inspection systems offering ease of setup, reduction in conveyor space, and more reliable inspection of packages such as cigarette packages.
According to a first embodiment, the invention provides an inspection apparatus for detecting and removing non-conforming packages traveling along a conveyor path, the apparatus comprising a conveyor transporting a plurality of identical packages along a conveyor path, at least one light source illuminating one of the packages at an inspection station along the conveyor path, a first detection device outputting a first signal representing presence of a first non-conforming condition of the package at the inspection station, a second detection device outputting a second signal representing presence of a second non-conforming condition of the package at the inspection station, a first ejection mechanism operable to remove a package having a first non-conforming condition, a second ejection mechanism operable to remove a package having a second non-conforming condition, and a controller operable to process data generated in response to the first and second signals and track packages having the first and/or second non-conforming conditions, the controller being further operable to activate the first and second ejection mechanisms to remove non-conforming packages from the conveyor path.
In accordance with the first embodiment, the first detection device can comprise a foil detection sensor outputting foil signals representing presence of a foil wrapper of the package at the inspection station and the second detection device can comprise at least one camera outputting camera signals representing images of one or more surfaces of the package at the inspection station. In such a case, the first ejection mechanism is operable to remove a package having a non-conforming foil wrapper and the second ejection mechanism is operable to remove a package having a non-conforming image.
In accordance with the first embodiment, the invention provides a method of detecting and removing non-conforming packages traveling along a conveyor path, the method comprising transporting a plurality of identical packages along a conveyor path, operating a first detection device to output a first signal representing a first non-conforming condition of a package at an inspection station along the conveyor path, operating a second detection device to output a second signal representing a second non-conforming condition of a package at the inspection station, operating a controller to track packages having the first and second non-conforming conditions, and operating the controller to activate a first ejection mechanism to remove a package having a first non-conforming condition when the non-conforming package is at an ejection station along the conveyor path, and operating the controller to activate a second ejection mechanism to remove a package having a second non-conforming condition when the non-conforming package is at the ejection station. In a preferred method, the first detection device comprises a foil detection sensor which outputs foil signals representing a foil condition of a foil wrapper of a package at the inspection station and the second detection device comprises at least one camera which outputs camera signals representing at least one surface condition of a package at the inspection station, the method including processing the camera signals and the foil signals to identify a package at the inspection station which contains a non-conforming surface feature or non-conforming foil wrapper.
According to a second embodiment, the invention provides an inspection apparatus for visually detecting non-conforming packages traveling along a conveyor path, the apparatus comprising a conveyor transporting a plurality of identical packages along a conveyor path, a light source illuminating one of the packages at an inspection station along the conveyor path, the light source illuminating the package at the inspection station using a diffuse lighting source which includes a light reflector and at least one fiber optic lighting element, the at least one fiber optic lighting element delivering a pulsed beam of light to the light reflector while a package is located at a camera inspection position, and the light reflector illuminating the package with diffused light reflected from a surface of the light reflector, at least one camera outputting camera signals representing images of one or more surfaces of the package at the inspection station, and a controller operable to process data generated in response to the camera signals and identify a package having a non-conforming surface feature.
According to the second embodiment, the invention additionally provides a method of visually detecting non-conforming packages traveling along a conveyor path, the method comprising transporting a plurality of identical packages along a conveyor path, illuminating one of the packages at an inspection station along the conveyor path, the package being illuminated at the inspection station using a diffuse lighting source which includes a light reflector and at least one fiber optic lighting element, the at least one fiber optic lighting element delivering a pulsed beam of light to the light reflector while a package is located at a camera inspection position, and the light reflector illuminating the package with diffused light reflected from a surface of the light reflector, outputting camera signals representing images of one or more surfaces of the package at the inspection station, and processing data generated in response to the camera signals so as to identify a package having a non-conforming surface feature. According to this method, the package can be illuminated using a plurality of fiber optic elements delivering pulsed beams of light into the reflector, the reflector including a flat white coating on a surface thereof facing the package to be inspected. The reflector can include a housing which surrounds a vertically oriented conveyor belt, the method including using a conveyor belt traveling over a vacuum chamber to apply a vacuum force to the belt to hold a package thereon as it travels through the inspection station.